The refugee crisis roiling Europe presents a win-win opportunity for Islamic State (IS) extremists, says international terrorism research consultancy TRAC.By hiding among thousands of asylum-seekers, the Islamist militants can expand their operational presence in Europe, the consortium of analysts warned in a briefing released Thursday.And if any of their infiltrated members are caught, the backlash could help radicalize disaffected European Muslims.“This presents mounting challenges for the EU where it is compelled to find the thin line between allowing the entry of refugees whilst weeding out terror operatives or a blanket order of shutting its doors to refugees,” the TRAC briefing read in part.Despite fears that IS is exploiting the refugee crisis to infiltrate Europe by disguising members as asylum-seekers, only six cases have so far been reported. Analysts, however, say the apparently meager numbers shouldn’t be a cause for relief or a source of complacency — a point echoed by European intelligence officials who VOA spoke to on condition of anonymity.The most alarming case of infiltration came in May when Italian police announced they had arrested Abdel Majid Touil, a Moroccan national, whom they accuse of helping to plan the March 18 terror attack on the Bardo Museum in Tunis, which left 22 people — mainly tourists — dead.According to Bruno Megale, head of Italy's anti-terror police, the Moroccan smuggled himself into Italy aboard a vessel with 90 other migrants in February just before the attack and was arrested in the Italian village of Gaggiano, southwest of Milan, where his mother and two older brothers live.His arrest caused consternation in Rome and prompted an outcry from anti-immigration politicians. The head of the Northern League party, Matteo Salvini, called for the suspension of the Schengen agreement allowing passport-free travel within EU countries and the closing of Italy’s borders. “Libyan intelligence says boats are arriving with Islamic State terrorists," Salvini announced.

Multiple casesMost of the half-dozen reported incidents of suspected jihadists entering Europe alongside migrants have occurred month. Five men in their twenties suspected of links to IS attempted to cross the Macedonia-Bulgaria border on September 3, but were promptly arrested following a failed attempt to bribe a border security officer.On September 9, the Hungarian media reported that 30-year-old Laith Al Saleh, an alleged IS member, had already passed through the country as a refugee and reached Germany. Also on September 9, a suspected IS operative, a Moroccan national with a German passport, was detained by Bulgarian authorities and extradited to Germany. The 21-year-old suspect was detained trying to cross from Turkey into Bulgaria using a forged Syrian passport.Also this month, German authorities arrested another suspected IS member, a Moroccan in possession of forged Syrian passports, in a refugee center in Stuttgart. Attempting to infiltrate the contitent as an asylum, he was identified after German police linked him to a European arrest warrant issued by Spanish authorities.European intelligence officials say they would be concerned if even a few IS members slipped into Europe unnoticed. They are especially alarmed about the prospect of returning European-born fighters evading detection.“Their familiarity with their home countries makes them even more dangerous,” said one Paris-based intelligence official.“The numbers don’t have to be large. Think of the storm caused by the action of just three men here in Paris in January,” he added, referring to the massacre that left 12 at the satirical Charlie Hebdo magazine dead and a suburban kosher market shooting in which four Jewish shoppers were killed.With the increasingly common focus on soft targets in Europe, jihadists needn't be large in number or possess much logistical backup typically required of more complex terror plots. In the face of terrorism going for “low-grade” and commonplace targets, Western governments are hard-pressed to offer security or even reassurance that they can foil random attacks against targets that lack obvious symbolic significance.In some ways, the departure from highly complex attacks like those of September 11, 2001, which killed nearly 3,000 people, and those of July 2005 in London, which left 56 people dead and 700 injured, is a reflection of how adept intelligence and law enforcement agencies have become in foiling larger plots — and forcing the extremists to aim for easier targets.In Britain alone, security services are hard pressed, monitoring some 350 Britons who have returned from the battlefields of Syria."The tempo in terms of counterterrorism and law enforcement is the highest it has ever been," says former anti-terror chief Peter Clarke.In Italy, anti-terrorism detectives suspect an active jihadist network is still plotting terror attacks on Rome, including the Vatican, despite a series of recent arrests.